1. Field of the Invention
The present invention relates to a process for producing a fluorovinyl ether. More particularly, it relates to a novel process for producing a fluorovinyl ether by a deiodofluorination of a specific iodine-containing ether with a metal component.
2. Description of Prior Arts
It has been known that fluorovinyl ethers have been produced by a reaction of a fluoroolefin with an alkali metal alkoxide as the production of methoxytrifluoroethylene. However, such process is not suitable for the production of perfluorovinyl ethers because of low yield and difficult industrial operation.
It has been known that perfluorovinyl ethers can be produced by reacting a fluorinated acid fluoride with hexafluoropropylene epoxide and converting the product by a thermal reaction as disclosed in Japanese Patent Publication No. 1617/1963 and U.S. Pat. No. 3,114,778.
The process for using hexafluoropropylene epoxide as the starting material is remarkably effective as the process for producing fluorovinyl ethers. However, it is seriously disadvantageous because of expensive process in view of the commercial availability and the yield.
The inventors have studied to provide a process for producing fluorovinyl ehters without using hexafluoropropylene epoxide. As a result, the following facts have been found.
An iodine-containing fluoroether can be produced at high yield by reacting an acid fluoride with tetrafluoroethylene, I.sub.2 and KF. The iodine-containing ether can be easily reacted with a metal such as zinc in an organic solvent and the reaction product is easily converted by heating into the corresponding fluorovinyl ether at high yield.
It has been well-known that Rf'I (Rf' represents a perfluoroalkyl group) into R"f--CF.dbd.CF.sub.2 (R"f represents a perfluoroalkyl group) with an organomagnesium compound or Zn-Cu as disclosed in J.O.C. 36 364. (1971) and Tetrahedron 33, 2061, (1977). However, the isomerization of the product is carried out to decrease the yield of the object compound and the separation and the isolation are not easy.
The isomerization of the fluorovinyl ethers having the formula XRfCF.sub.2 OCF.dbd.CF.sub.2 is not resulted to give high selectivity in the production and the separation and the isolation of the product are remarkably easy.
The vinyl etherification by the deiodofluorination is suitable for the production of the perfluorovinyl ether.